 
<head>
<script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jquery/1.5.0/jquery.min.js"></script>
    <script type="text/javascript" src="http://ajax.googleapis.com/ajax/libs/jqueryui/1.8.1/jquery-ui.min.js" ></script>
<script type="text/javascript">
    $(document).ready(function(){
        $("#u").draggable();
    });
    
</script>    
</head>
<body>
    <div id="u" style="width: 100px;height: 100px;background-color: #0590B9">
        
        </div>
</body>